Multiple-input multiple-output (MIMO) devices typically benefit from antennas able to optimize the transmission path signal level. However, the direction of the optimal signal path may vary and is often difficult to predict. An antenna which can be configured to have a radiation pattern directed in the optimal or more optimal direction may potentially increase signal level and data rate for wireless communications.
Various antennas may be used in wireless communication devices, including user equipment (UE) devices and access point (AP) devices. Similarly, a number of antennas may be used in wireless local area network (WLAN) devices for providing users with access to services and/or network connectivity. Antennas may also be elements in antenna arrays, which may perform beamforming and beamsteering operations. An antenna may be selected or designed according to various parameters, such as desired antenna polarization and radiation pattern (for example, beam peak and null direction).
In general, a larger number of antennas on a single radio port may be useful for achieving a better transmission path and/or better interference nulling. For smaller or more compact devices, it may be a challenge to implement larger number of antennas, particularly at lower frequencies (e.g., 3.5 GHz). In particular, antenna size typically increases with lower operating frequencies, which limits the number of elements that can be implemented on the device. It is desirable to provide a solution for achieving higher antenna density in devices, while maintaining key performance features such as polarization diversity, high directionality and/or wide frequency bandwidths.